A comprehensive analysis of the $B^0\to K^{*0}\mu^+\mu^-$ decay

TL;DR

This paper provides a detailed analysis of the $B^0 o K^{*0} o K^+\pi^-\,\mu^+\,\mu^-$ decay, measuring angular observables and branching fractions using LHCb data, confirming previous tensions with the Standard Model.

Contribution

It presents the first comprehensive measurement of all angular observables, including $K^+\pi^-$ S-wave contributions, and considers muon mass effects in this decay.

Findings

Observables show persistent tensions with Standard Model predictions.

No significant $CP$-asymmetry deviations from zero are observed.

Full set of $CP$-averaged and $CP$-asymmetric observables are reported.

Abstract

An analysis of the $B^{0}\rightarrow K^{*0}(\to K^+ \pi^-)\mu^{+}\mu^{-}$ decay is presented using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 8.4 fb$^{-1}$. The full set of $CP$-averaged and $CP$-asymmetric angular observables is determined in bins of the invariant mass squared of the dimuon system, as well as the branching fraction relative to the $B^{0}\rightarrow J/\psi(\to\mu^{+}\mu^{-})K^+\pi^-$ decay. For the first time, the full set of observables pertaining to the $K^+\pi^-$ S-wave contribution to the final state are presented and consideration is given to effects arising from the mass of the muons. The measurements of the $CP$-averaged observables and the branching fractions continue to exhibit the pattern of tensions with the Standard Model predictions that have been seen in previous analyses that use part of the dataset considered in this study. The extracted $CP$-asymmetry observables show no significant deviations from zero.